Many materials are stored in warehouses on pallets, either on the ground or above ground on racking. Aisles between the palletised materials allow the operator of pedestrian-operated forklift trucks to select whatever pallet they require. However, the aisles need to have a certain minimum width to allow unrestricted operation of the trucks. This will now be described with reference to FIGS. 1a and 1b. 
FIG. 1a is a schematic top plan view of a conventional pedestrian-operated forklift truck. The truck comprises a chassis 10 having left and right non-steerable, non-driven front wheels 12L, 12R respectively and a steerable rear drive wheel 14 disposed centrally between, but rearwardly displaced, relative to the front wheels. The chassis 10 carries a conventional lifting mechanism such as a mast 16 and lift forks 18. In some trucks with tillers the lift forks are replaced by lift platforms. The rear wheel 14 is directly or indirectly connected to a steering tiller 20 by a mechanical, hydraulic, electrical or other coupling. The truck is controlled from a tiller head 22, mounted at the free rear end of the tiller 20, by a pedestrian operator 24. A traction motor (not shown in FIGS. 1a and 1b) drives the steerable rear wheel 14 in forward or reverse directions about a horizontal rotation axis 26 under the control of manually operable control members (also not shown) on the tiller head 22.
The rear wheel 14 is steerable by rotation about a substantially vertical axis by rotation of the tiller 20. The connection between the tiller 20 and the rear wheel 14 is such that when the tiller 20 is rotated through a certain angle the rear wheel 14 follows suit so that the rear wheel 14 is always in line with the tiller 20; i.e. the horizontal rotational axis 26 of the rear wheel 14 is always normal to a vertical plane containing the tiller 20.
Conventional pedestrian-operated forklift trucks as described above normally operate in an aisle 30 (FIG. 1b) between two parallel rows 32 of palletised product. In order to pick up any particular pallet the truck needs to be initially positioned at right angles to the row 32 with the tiller 20 extending directly to the rear, as shown in FIG. 1b. This means that the aisle 30 must have a minimum width W equal to the total length of the truck. The required steering space S is necessary but effectively wasted storage space.